Scavenging behavior of schumannianthus dichotomus-derived activated carbon for the removal of methylene blue from aqueous phase



In this article, the decoloration capacity of acid-activated Schumannianthus dichotomus (ASD) toward a model organic cation is described: methylene blue (MB) from aqueous phase. The characterization of the developed adsorbent was focused on proximate, ultimate analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, surface area, and porosity analysis to understand the adsorbent–adsorbate retention as well as interpretation of experimental results. It has been found that adsorbent is essentially microporous–mesoporous in nature with Brunauer–Emmett–Teller surface area of 1199.98 m2 g−1. The effect of various operating parameters on adsorption such as pH, adsorbent dose, contact time, and temperature was monitored. The suitability of Freundlich, Langmuir, and Temkin adsorption models to the experimental data was investigated for MB-adsorbent system. The results showed that equilibrium data for all MB-adsorbent system fitted the Langmuir model best (R2 = 0.99), yielding monolayer adsorption capacity of 336.70 mg g−1 at 303 K. The pseudo-second-order kinetic model provides best correlation (R2 = 0.999) of the experimental data with rate constant of 0.0157 g mg−1 min−1. The thermodynamics parameters ΔGº, ΔHº, and ΔSº evaluated as −9.51 (kJ mol−1), −36.16 (kJ mol−1), and −87.93 (J mol−1 K−1), respectively, revealed that adsorption process is feasible, spontaneous, and exothermic in nature. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1148–1157, 2014